Sure, I think I can help. This are the courses that I remember approach things with optimization in mind. From newer to older:
https://cgcookie.com/courses/rev-model-a-low-poly-muscle-car
https://cgcookie.com/courses/cubicity-creating-and-utilizing-asset-libraries-with-blender
https://cgcookie.com/courses/press-start-your-simple-first-blender-project
https://cgcookie.com/courses/creating-a-stylized-3d-forest-environment-with-blender-2-9
https://cgcookie.com/courses/build-and-animate-a-low-poly-rocket-in-blender-for-beginners
https://cgcookie.com/courses/animated-sci-fi-game-environment-creation-in-blender-2-8
https://cgcookie.com/courses/creating-mini-tanks-for-a-mobile-game-with-blender-2-8
https://cgcookie.com/courses/modeling-weapons-for-a-first-person-shooter
https://cgcookie.com/courses/creating-hair-cards-for-realtime-characters
https://cgcookie.com/courses/game-character-modeling-with-blender
https://cgcookie.com/courses/building-modular-game-assets
https://cgcookie.com/courses/modeling-video-game-assets-in-blender
https://cgcookie.com/courses/texturing-game-assets-with-blender